Visual Basic.NET - Quiero migrar a VB.NET como pasar este pequeño codigo

Option Explicit

Public Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" (ByVal sAgent As String, ByVal lAccessType As Long, ByVal sProxyName As String, ByVal sProxyBypass As String, ByVal lFlags As Long) As Long

Public Declare Function InternetOpenUrl Lib "wininet.dll" Alias "InternetOpenUrlA" (ByVal hInternetSession As Long, ByVal sURL As String, ByVal sHeaders As String, ByVal lHeadersLength As Long, ByVal lFlags As Long, ByVal lContext As Long) As Long

Public Declare Function InternetReadFile Lib "wininet.dll" (ByVal hFile As Long, ByVal sBuffer As String, ByVal lNumBytesToRead As Long, lNumberOfBytesRead As Long) As Integer

Public Declare Function InternetCloseHandle Lib "wininet.dll" (ByVal hInet As Long) As Integer

Public Const IF_FROM_CACHE = &H1000000

Public Const IF_MAKE_PERSISTENT = &H2000000

Public Const IF_NO_CACHE_WRITE = &H4000000

Private Const BUFFER_LEN = 256

Public Function GetUrlSource(sURL As String) As String

    Dim sBuffer As String * BUFFER_LEN, iResult As Integer, sData As String

    Dim hInternet As Long, hSession As Long, lReturn As Long

    'get the handle of the current internet connection

    hSession = InternetOpen("vb wininet", 1, vbNullString, vbNullString, 0)

    'get the handle of the url

    If hSession Then hInternet = InternetOpenUrl(hSession, sURL, vbNullString, 0, IF_NO_CACHE_WRITE, 0)

    'if we have the handle, then start reading the web page

    If hInternet Then

        'get the first chunk & buffer it.

        iResult = InternetReadFile(hInternet, sBuffer, BUFFER_LEN, lReturn)

        sData = sBuffer

        'if there's more data then keep reading it into the buffer

        Do While lReturn <> 0

            iResult = InternetReadFile(hInternet, sBuffer, BUFFER_LEN, lReturn)

            sData = sData + Mid(sBuffer, 1, lReturn)

        Loop

    End If

    'close the URL

    iResult = InternetCloseHandle(hInternet)

    GetUrlSource = sData

End Function

Dim sourceString As String = New System.Net.WebClient().DownloadString("http://www.dominio.es/pagina")

Dim html As String

Dim request As WebRequest = WebRequest.Create("http://www.dominio.es/pagina")

Using response As WebResponse = request.GetResponse()

    Using reader As New StreamReader(response.GetResponseStream())

        html = reader.ReadToEnd()

    End Using

End Using